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Message-ID: <3e2245953c143b55d512d46a16ed8a2c@codeaurora.org>
Date: Thu, 07 Jan 2021 16:58:23 +0800
From: Can Guo <cang@...eaurora.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
kernel-team@...roid.com, alim.akhtar@...sung.com,
avri.altman@....com, bvanassche@....org,
martin.petersen@...cle.com, stanley.chu@...iatek.com
Subject: Re: [PATCH v4 2/2] scsi: ufs: handle LINERESET with correct tm_cmd
On 2021-01-07 16:46, Jaegeuk Kim wrote:
> On 01/07, Can Guo wrote:
>> On 2021-01-07 16:07, Jaegeuk Kim wrote:
>> > On 01/07, Can Guo wrote:
>> > > On 2021-01-07 15:47, Jaegeuk Kim wrote:
>> > > > From: Jaegeuk Kim <jaegeuk@...gle.com>
>> > > >
>> > > > This fixes a warning caused by wrong reserve tag usage in
>> > > > __ufshcd_issue_tm_cmd.
>> > > >
>> > > > WARNING: CPU: 7 PID: 7 at block/blk-core.c:630 blk_get_request+0x68/0x70
>> > > > WARNING: CPU: 4 PID: 157 at block/blk-mq-tag.c:82
>> > > > blk_mq_get_tag+0x438/0x46c
>> > > >
>> > > > And, in ufshcd_err_handler(), we can avoid to send tm_cmd before
>> > > > aborting
>> > > > outstanding commands by waiting a bit for IO completion like this.
>> > > >
>> > > > __ufshcd_issue_tm_cmd: task management cmd 0x80 timed-out
>> > > >
>> > > > Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to
>> > > > allocate and free TMFs")
>> > > > Fixes: 2355b66ed20c ("scsi: ufs: Handle LINERESET indication in err
>> > > > handler")
>> > >
>> > > Hi Jaegeuk,
>> > >
>> > > Sorry, what is wrong with commit 2355b66ed20c? Clearing pending I/O
>> > > reqs is a general procedure for handling all non-fatal errors.
>> >
>> > Without waiting IOs, I hit the below timeout all the time from
>> > LINERESET, which
>> > causes UFS stuck permanently, as mentioned in the description.
>> >
>> > "__ufshcd_issue_tm_cmd: task management cmd 0x80 timed-out"
>>
>> In that case, ufshcd_try_to_abort_task(), the caller of
>> __ufshcd_issue_tm_cmd(),
>> should return -ETIMEOUT, then err_handler would jump to do a full
>> reset,
>> then bail.
>> I am not sure what gets UFS stuck permanently. Could you please share
>> the
>> callstack
>> if possible? I really want to know what is happening. Thanks.
>
> I can't share all the log tho, it entered full reset. While printing
> out
> whole registers, the device was hard reset. Thanks,
Hi Jaegeuk,
Entering full reset is expected in this case, which is why I am saying
line-reset handling logic should not be penalized. I think we need to
find out what caused the hard reset but not just adding a delay before
clearing pending reqs, because let's say 3 sec expires and you hit the
same tm req timeout (maybe with a lower possibility), you may still end
up same at the hard reset. You don't need to share all the log, just the
last call stacks before hard reset. Is it a QCOM's platform used in your
case? Can you check the log/dump if NoC error happened?
Thanks.
Can Guo.
>
>>
>> Regards,
>> Can Guo.
>>
>> >
>> > >
>> > > Thanks,
>> > > Can Guo.
>> > >
>> > > > Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>> > > > ---
>> > > > drivers/scsi/ufs/ufshcd.c | 35 +++++++++++++++++++++++++++++++----
>> > > > 1 file changed, 31 insertions(+), 4 deletions(-)
>> > > >
>> > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> > > > index e6e7bdf99cd7..340dd5e515dd 100644
>> > > > --- a/drivers/scsi/ufs/ufshcd.c
>> > > > +++ b/drivers/scsi/ufs/ufshcd.c
>> > > > @@ -44,6 +44,9 @@
>> > > > /* Query request timeout */
>> > > > #define QUERY_REQ_TIMEOUT 1500 /* 1.5 seconds */
>> > > >
>> > > > +/* LINERESET TIME OUT */
>> > > > +#define LINERESET_IO_TIMEOUT_MS (30000) /* 30 sec */
>> > > > +
>> > > > /* Task management command timeout */
>> > > > #define TM_CMD_TIMEOUT 100 /* msecs */
>> > > >
>> > > > @@ -5826,6 +5829,7 @@ static void ufshcd_err_handler(struct work_struct
>> > > > *work)
>> > > > int err = 0, pmc_err;
>> > > > int tag;
>> > > > bool needs_reset = false, needs_restore = false;
>> > > > + ktime_t start;
>> > > >
>> > > > hba = container_of(work, struct ufs_hba, eh_work);
>> > > >
>> > > > @@ -5911,6 +5915,22 @@ static void ufshcd_err_handler(struct work_struct
>> > > > *work)
>> > > > }
>> > > >
>> > > > hba->silence_err_logs = true;
>> > > > +
>> > > > + /* Wait for IO completion for non-fatal errors to avoid aborting IOs
>> > > > */
>> > > > + start = ktime_get();
>> > > > + while (hba->outstanding_reqs) {
>> > > > + ufshcd_complete_requests(hba);
>> > > > + spin_unlock_irqrestore(hba->host->host_lock, flags);
>> > > > + schedule();
>> > > > + spin_lock_irqsave(hba->host->host_lock, flags);
>> > > > + if (ktime_to_ms(ktime_sub(ktime_get(), start)) >
>> > > > + LINERESET_IO_TIMEOUT_MS) {
>> > > > + dev_err(hba->dev, "%s: timeout, outstanding=0x%lx\n",
>> > > > + __func__, hba->outstanding_reqs);
>> > > > + break;
>> > > > + }
>> > > > + }
>> > > > +
>> > > > /* release lock as clear command might sleep */
>> > > > spin_unlock_irqrestore(hba->host->host_lock, flags);
>> > > > /* Clear pending transfer requests */
>> > > > @@ -6302,9 +6322,13 @@ static irqreturn_t ufshcd_intr(int irq, void
>> > > > *__hba)
>> > > > intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
>> > > > }
>> > > >
>> > > > - if (enabled_intr_status && retval == IRQ_NONE) {
>> > > > - dev_err(hba->dev, "%s: Unhandled interrupt 0x%08x\n",
>> > > > - __func__, intr_status);
>> > > > + if (enabled_intr_status && retval == IRQ_NONE &&
>> > > > + !ufshcd_eh_in_progress(hba)) {
>> > > > + dev_err(hba->dev, "%s: Unhandled interrupt 0x%08x (0x%08x,
>> > > > 0x%08x)\n",
>> > > > + __func__,
>> > > > + intr_status,
>> > > > + hba->ufs_stats.last_intr_status,
>> > > > + enabled_intr_status);
>> > > > ufshcd_dump_regs(hba, 0, UFSHCI_REG_SPACE_SIZE, "host_regs: ");
>> > > > }
>> > > >
>> > > > @@ -6348,7 +6372,10 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba
>> > > > *hba,
>> > > > * Even though we use wait_event() which sleeps indefinitely,
>> > > > * the maximum wait time is bounded by %TM_CMD_TIMEOUT.
>> > > > */
>> > > > - req = blk_get_request(q, REQ_OP_DRV_OUT, BLK_MQ_REQ_RESERVED);
>> > > > + req = blk_get_request(q, REQ_OP_DRV_OUT, 0);
>> > > > + if (IS_ERR(req))
>> > > > + return PTR_ERR(req);
>> > > > +
>> > > > req->end_io_data = &wait;
>> > > > free_slot = req->tag;
>> > > > WARN_ON_ONCE(free_slot < 0 || free_slot >= hba->nutmrs);
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